Elastic-fluid compressor



Jan. 5, 19 26.

1,568,708 c. A. BAKER ELASTIC FIQUID COMPRESSOR le y 10. 1924 4 Shets-Sheet 1 3a a4 z4 as as V l l l l Y 3W: 7 5' CA'flAZm.

Y 1,568,708 0. A. BAKER 4 ELASTIC FLUID COMPRESSOR Filed May 1924 v 4 Sheets-:Sheet '2' @uuewtoc:

ACAHBAKER.

Jan. 5 1926.

C. A. BAKER ELASTIC FLUID COMPRESSOR v c. A. BAKER ELASTIC FLUID COMPRESSOR 4 Sheets-Sheet 4 Filed May 10, 1924 lllllll M gluuzwtoz:

' V CA.5AKER.

Patented Jan. 5, 19260 UNITED; STATES enns'jrna A. BAKER, F OMAHA, nnBnAs A.

ELASTIC-FLUID 'oorrr'ansson.

Application filed my "10, 1924. Serial no; 712,332.

1 107mm it may concern:

" Be it known that I, Cr-msrE'R A. B K R, a

citizen of the United States, tesi'ding at Omaha, in the county of Douglas and State of Nebraska, have invented certain new and 11seful Improvements in Elastic-Fluid Coinpasser-s, of which the following is a specification. 4 I

My inventionrela'tes to compressors for elastic fluids such as air, ammonia, sulphur dioxide, and the like. I Itis the object of my invention to provide'in a compressor of this class an improved valve mechanism, or

means for cont-rolling the admission and discl'iarge of the nncom'pressed and compressed elastic fluid to and from the cylinder. A further object of my invention is to provide fluid until the pressure at the discharge passage'h'as been lowered, thereafter resuming 9 the deli ery automatically. A further object is to provide a valve mechanism for elastic-fluid compressors, with which the accidentalintroduction of liquids or inelastic fluids tothe' compressoncylinder will automatically effect an enlargement of the compression space at the end ofthe compression 7 stroke of the p ston, suflicient to compensate for the inducted volume of liquid, and thereby preventiexcessive cylinder-pressures resulting from the presence of suchinelastic fluids. l

In the accompanying drawings, Fig. 1 is .a vertical transverse section of a compressor embodying my invention, Fig. 2 is a partial longitudinal vertical section of the same,

el ligs. 3, 4-, 5 and 6 are partly diagrammatic vertical sectionalviews, showing various positions in the cycle of operation of the valvemechanism, Fig. '7 is a horizontal section on the oii set plane of the line 7-7 of Fig. 3, Fig. 8 is a detail vertical section of the upper portion of the cylinder,in a slightly modified structure, and Fig. 9 is vertical section of the lower portion of the cylinder,

s'howin g a modified means for limiting the "through the lox ver flange '23.

lower end,

downward stroke of'the valve-sleeve and lifting the same to lap position.

In the structure illustrated in Figs. l'to 7, inclusive, I provide a crank-casing 10 having i'nclose'd bearings 11 and 12 fora crank-shaft 13 which at one end extends through a paoking-gland'l, the projecting portion of the shaft passing through a p'ed estal-bearing 15 and carrying a fly-wheel 16. At the sides of the crank-casing other than that carrying the gland 14, are removable plates 1'7 which provide access to the crank and connecting-rodfor inspection or adjustment. The crank 18 is connected with the piston 19 by a connecting-rod 20 of ordinary form. The cylinder 21 is mounted on i the upper side of the crank-casing, being secured thereto by stud-bolts 22 passing The upper portion of the cylinder is enlarged and cored to provide a acket 'space 24, to which the pipes 25 and 26 are connected at opposite sides, as shown in Fig. 2, so that water or other cooling medium maybe circulated through said jacket spa'ce jacket-space 24, and suitably partitioned Beneath the therefrom, is an annular chamber 27 having atone side of the cylinder an external openlng to which Is connected the SllCi lOIlr pipe QSthrQugh which the compressibl fluid is supplied, Aremovable"cylinder-head 29 U cylinder is counterbored to receive the fixed sleeve or bushing 30 which is of the same "bore or internal'dianieter as the lower portiono'f the cylinder, whereby to form substantially a continuation thereof. In the outer portion of said bushing 30, near its is an annular groove or channel forming a chamber 31 which is in communication with the "disch'argeor delivery pipe 'is provided, and adjacent to said head the 82, thelatter beingdisposed at the side of the cylinder opposite the suction-pipe 28.

' The valve-sleeve 33 fits slidably within the cylinder-'21, the upper portion of said sleeveextending into the lower portion of the bushing 30, and near its upper-end the sleeve has a head 34, whereby a closed space or pressure-chamber 35 is formed between said sleeve-head 34 and the cylinder-head 29. The piston 19 fits slidably, within the valve-sleeve below the head 34:. t In the walls of the valve-sleeve, below and adjacent to a the head 34, are a s'eries of ports 36 which,

by suitable movements of the sleevelongitudinally of the. cylinder, may come into I register with ports 37 extending through the cylinder-wall to the suction-chamber 27, or into register with ports 38 which extend through the bushing-wall to the dischargechamber 31. The piston 19 has expansible packing-rings fitting in grooves therein in the usual manner, and the valve-sleeve has similar packing-rings 39 fitting in grooves above and below the ports 36. From the discharge-chamber 31 a small port 40 is extended up through the bushing 30 to comnninicate with the pressure-chamber Vithin the crank-case, vertically alined with one side of the valve-sleeve, there is a fixed guide 4-1 for a push-rod 42, of which the lower end carries av shoe 43 engaging a cam ll secured on the crank-shaft. A coil spring l5 is arranged about the rod 42 between the guide ll and shoe 43, the pressure of said spring serving to hold the shoe against the cam. About the upper part of the pushrod, which projects above the guide 41, there is disposed a spring 46 of which the free height is such that it extends above the end of the rod. Said spring 46, by engagement with the lower end of the valvesleeve, yieldingly resists downward movement of said sleeve, and the upper end of the push-rod 42 forms a stop or abutment for positively limiting downward movement of the sleeve.

The operation of the described structure may now be readily understood. \Vhen the valvesleeve is in a lowered position such as shown in Figs. 3 and at, the port 40 supplies to the chamber 35 the same pressure that exists in the discharge-pipe 32, and said pressure is exerted upon the sleevehead 34:, thus tending to move the sleeve downwardly. From the positions of the parts shown in Fig. l, the piston commences its downward or suction stroke, and during the first part of said stroke the valve-sleeve moves with the piston. is the lower end of the sleeve engages the spring 46 the movement of the sleeve is yieldingly resisted by said spring, the resistance increasing as the spring is compressed. Should the compression of the spring to become sufiicient to equal the head-pressure in the chamber 35, the continued downward movement of the piston will produce a partial vacuum in the chamber 47 between the piston and sleevehead, which will cause the movement of the sleeve to be continued until the lower end thereof engages the push-rod 42, and at this position the sleeve-ports 36 will be in register with the suction-ports 37, as represented in Fig. 3. Then during the remainder of the downward stroke of the piston a charge will be drawn through the ports 36 and 37 into the piston-space or Cllflll'llJT-l' 47. The cam 4% is so proportioned and arranged that just prior to the completion of the downard stroke of the piston said cam will begin to raise the push-rod and thereby lift the valve-sleeve. The extent of movement imparted to the sleeve is such that the intake ports will be closed as the crank reaches the bottom deadcenter, and the lifting of the sleeve by the cam is continued until the sleeve is in the intermediate or lap position shown in Fig. 4. During the upward movement of the piston the same compresses the charge in the chamber 47 until the pressure therein becomes efi'ective in counterbalancing the head-pressure from the chamber 35, and the valve-sleeve will then commence to move upward by reason of the pressure of the spring 46, the relation of the parts being as represented in Fig. 5. By further upward movement of the piston the pressure upon the charge in the chamber 47 exceeds the head-pressure in the chamber 35, and the valve-sleeve is thereby moved up to a position at which the ports 36 come into register with the discharge-ports 38, as shown in Fig. 6. Upon the opening of the discharge-ports the excess pressure of the charge in the chamber 47 is relieved by delivery of portions thereof through said ports, so that no further movement of the sleeve occurs during the remainder ot the upward stroke of the piston.

Referring now to the modified structure shown in Fig. 8, it will be noted that the discharge-pipe 32 is connected directly with the chamber above the head of the valvesleeve, so that the discharge pressure is constantly upon the sleeve-head. The bushing 30 is omitted, and about the walls of the upper chamber, integral with the cylinder, are a plurality of inwardly extending ribs 48 of which the inner edges are bored concentrically with the cylinder, whereby to confine the packing-rings 39 in that portion of the valve-sleeve which extends up into the head-chamber. In the discharge position of the valve-sleeve the ports 36 open to the HPZUJGS between the ribs 46, said spaces forming discharge-ports which communicate with the head-chamber. The cylinder-head 29 is provided with a central lug 49 which extends down into the head-chamber, and about said lug is disposed a coil spring 50 of which the upper end is attached to the cylinder-head by means of a ring 51 engaging the upper convolution of the spring. Said spring 50 is so proportioned as to be under compression when the valve-sleeve is in the discharge position shown in the Fig. 8, and the pressure of the spring is thereby effective to move the sleeve downwardly for closing the discharge-ports when the piston begins its downward stroke, should the discharge or head-pressure upon the sleeve be insullicient to etlect said closing movement. The limit of expansion of the :pring In) is reached when the sleeve is in the lap position, and during the remainder of the doxvnward stroke of the sleeve the spring remains suspended from the cylinder-head;

In the structure shown in Fig. 9, the crank-easinghas a ledge 52 which extends in beneath the lower end of the cylinder and valve-sleeve, and said led e supports a coil spring 46 of large diameter, positioned beneath the lower end of said sleeve. In this structure the cam and push-rod are omitted, and the spring 46 forms the sole means for hunting the downward movement of the valve-sleeve and for actuating said sleeve to the lap position to close the suctionports at the beginning of the compression stroke of the piston. This structure is suitable for use where it is desirable that the discharge-pressure of the compressed elastic fluid be automatically limited to a predetermined maximum. Said effect is attained by suitably proportioning the spring 46, so that if, the discharge-pressure is at the desired maximum the corresponding head-pressure upon the-valve-sleeve will be counterbalanced only when said spring is that degree of compression effected by movement of the valve-sleeve to a position at which the suction-ports are open. Under these conditions the suction ports will not be closed at the beginning of the upward stroke of the piston, and the charge drawn into the piston-space during the downward stroke will be expelled through the same ports during the upward stroke, until the end of the piston itself closes the sleeveports. The sleeve will then be lifted to the discharge position, but as the in-drawn charge was expelled through the suction ports instead of being compressed, there will be nothing delivered to the discharge ports. This idling action will continue until the discharge-pressure upon the sleeve-head falls below the established maximum. When this occurs, the upward pressure of the spring :6 will be sufficient to move the sleeve to the lap position at the beginning of the upward stroke of the piston, and the compressing action will be resumed.

When the pressure to be delivered by the compressor is variable, the first-described structure is used, employing the cam and push-rod for raising the valve-sleeve to lap position, and with said structure the opera i tion of the compressor is continuedwithout regard to the pressure of the discharge.

In a compressor constructed in accordance with my invention the same may be operated at a relatively high speed, whereby to attain a largeoutput from a small, light machine. High-speed operation is made possible by the smooth, balanced action of the valve mechanism, the valve-sleeve being effectively cushioned at each limit of its movement, and its motion being caused principally by variations of pressure at the opposite sideso-f the sleeve-head, fl'he valvesleeve is freely rotatable within the cylinder and about the piston, and, the frictional contact between the parts will cause more or less rotary movement. of the sleeve, which may assume indiscriminately any circumferential relation to the other parts. By reason of such. rotation of the sleeve, wear of the sleeve and cylinder walls will be equalised, and said parts will remain truly cylindrical in form, not wearing oblong as in structures where the piston works directly in. the cylinder. Then the cylinder and piston becomeworn, the wear maybe com pcnsated by replacement of the old valvesleeve with another of which the outside and inside diameters are such as to properly lit, respectively, the worn cylinder, and piston. Should liquid, or incompressible fluid be accidentally drawn into the cylinder, no damage to the compressor can result therefrom, as the excess pressure, resulting from the presence of the liquid, will be automath cally relieved by additional lift of the valvesleeve at the end of the compression-stroke of the piston, the action of the sleeve in this respect serving the purpose of the safetyhead devices commonly used for ammonia conngressors in refrigeration apparatus.

Now, having described my invention, what.

I claim and desire to secure by Letters Patent is:

1. In an elastic-fluid compressor, a cyline der having in the walls thereof inlet ports and discharge ports spaced apart longitudinally, a reciprocating piston, a valve-sleeve fitting slidably within the cylinder and about the piston, said sleeve having a head inclosing the space above the piston and having lateral ports communicating with said piston-space and adapted to register with the cylinder-ports to connect the same with the piston-space, means supplying elastic fluid pressure above the sleeve-head tending to move the sleeve downwardly in the cylinder, and means for limiting the downward movement of the sleeve and for lifting the same against the head-pressure while the piston is substantially at the end of its suction stroke.

2. In an elastic-fluid compressor, a cylinsleeve-head, whereby said pressure upon said head may hold the sleeve in lap position during the compression strokes of the piston until the pressure in the piston-space exceeds the pressure at the discharge ports.

3. In a structure as set forth in claim 2, a spring engageable with the valve-sleeve to resist yielding the downward movement of the sleeve as it approaches its lower limit.

4:. In a structure as set forth in claim 2, a cam moving in unison with the piston, and a member controlled by said cam and engageable with the valve-sleeve to limit the downward movements thereof, said cam and cam-controlled member being arranged to lift the sleeve to lap position when the piston is near the end of its suction strokes.

In a structure as set forth in claim 2, a canrcontrolled member forming a positive stop for limiting downward movement of the valve-sleeve, and a spring arranged to yieldingly resist said downward movement of the sleeve upon its approach to the positive stop.

6. In a structure as set forth in claim 2,

a cam-controlled member forming a positive stop for limiting downward movement of the valve-sleeve, and a spring arranged to yieldingly resist said downward movement of the sleeve adjacent to the positive stop, said spring and cam-controlled member adapted and ar 'anged to lift the valve-sleeve to lap position as the piston ends its suction strokes.

7. In an elastic fluid compressor, a cylinder, a reciprocating piston, a valve-sleeve fitting slidably between the piston and cylinder-walls and having ports adapted to register with inlet and discharge ports in the cylinder-walls, and means for actuating said sleeve reciprocatingly to register the sleeveports with the inlet ports during the suction strokes of the piston and to register the sleeve-ports with the discharge ports during a portion of the compression strokes of the piston, the valve-sleeve being freely rotatable whereby to assume indiscriminately varying circumferential relations to the cylinder and piston.

CHESTER A. BAKER. 

